Jay Leno restored a 1914 Baker Electric and he estimated (or somebody did, I think I heard this from a podcast) that if you were to fit one of those 'cars' with as many Modern Nissan Leaf or Model S cells as you could fit in the the old battery compartments, it would travel between 600 and 700 miles at the original speed of 25 miles an hour. Just because it weighs so little, being mostly wood and leather.

25mph is just about optimal speed for electric motor efficiency, and much above 40mph over half of a vehicle's energy is spent simply pushing air out of the way.